One must be clean, spiritually and physically, in the presence of kami. kami will not come where there is kegare or tsumi. At least, not the beneficial sort of kami we want to attract. In order to be clean, purification rituals are performed. Here is a link to an explanation of some of these rituals: Shinto Purification Rituals (QuickTime Player required  free).

(taboo, mourning, abhor, detestable)
(taboo, purification, avoid)
❖ Abstinence, or the avoidance of that which is magakoto, tsumi and kegare, and the removal of those states

saikai

さいかい

斎戒

sai (purification, avoid)
kai (admonition; commandment)  Buddhist term
❖ Observance of abstinence for a certain period of time before and after a religious ceremony by a participant
❖ The person remains secluded in a building called an imiya, abstains from sex, uses only bekka, bathes frequently, abstains from partaking of certain foods, avoids contact with death and sickness, and concentrates on religious concerns

kin (prohibition, ban, forbid)
ki (mourning, abhor, detestable)
❖ (taboo  day, time, direction, words, etc. that must be avoided)
❖ To forbid any contact with or proximity to things that should be abstained from

shin | kami (that which inspires feelings of reverence, awe, gratitude, fear/terror)
jin (person)
ki (homecoming, arrive at, lead to, result in)
itsu (one)
❖ (kami and man become as one)
❖ Return of the purifed human nature to kami status from which it has fallen because of kegare and tsumi